Hello I am new here and I hope I made the right decision on joining this forum.

I just want to know what is a good mental math book that will guide me to doing mathematics quickly and accurate. I just feel that I am too dependent on the calculator and I have a job that requires quick use of math in my head. I do want to get better at it. I am a student and my full time job right now is working at a warehouse. I count sometimes recount, add, subtract, multiply, divide, percentages and of course fractions. It will be nice to be shopping somewhere and looking at all the sales and knowing right away how much the sale price will be after taking away the percentage discount.

I currently own just one mental math book. It is the The Trachtenberg Speed System of Basic Mathematics. I am providing the link below.

I like this book but does not handle percentages, word problems and cognitive skills. Does anybody know the Trachtenberg book? Was it worth purchasing this book? I hope someone knows. I hope someone can help me with this question. Thank you.

I have to admit, I used to be in love with mental math few years back, but now IMHO if we want to become a liberal mathematician, then we must rely on advanced mathematical topics (real analysis, etc.) Unless if you happen to be Daniel Tammet; Tammet is not too gifted on general mathematics, but very gifted on only numbers. He said in his own book that he had just managed to pass algebra topics, but did excellent job in arithmetic.